1. Field of the Invention
The present invention relates to a motor controlling device and method, and more particularly to a motor controlling device and method for providing different switching phase signals during different stages of motor operation to enhance the motor starting capability and operating efficiency.
2. Description of the Related Art
FIG. 1 shows a conventional motor controlling device 1. The Hall sensor 12 of the motor controlling device 1 is used for detecting a switching phase signal generated by a motor 2 during operation. The motor driving circuit 11 of the motor controlling device 1 is electrically connected to the Hall sensor 12, and is used for receiving the switching phase signal from the Hall sensor 12 to generate a motor rotating speed controlling signal. After the motor rotating speed controlling signal generated by the motor driving circuit 11 is sent to the coil switching circuit 13, the coil switching circuit 13 will send the motor rotating speed controlling signal to a coil set 211 of the motor 2 in sequence, such that the coil set 211 can switch the current direction between two adjoining phases to achieve continuous operation of the motor 2. In addition, a pulse width modulation (PWM) generating circuit 14 is used for controlling a rotating speed of the motor 2.
Referring to FIG. 2A, the conventional motor 2 is composed of a stator 21 and a rotor 22. The majority of controlling methods of the motor 2 is using a single Hall sensor 12 to detect the switching phase signal of the motor 2 and output the switching phase signal to the motor driving circuit 11 to drive the motor 2. The Hall sensor 12 is disposed on the stator 21 of the motor 2 for detecting the N or S poles of the rotor 22 which passes through and then the Hall sensor 12 outputs a signal to change the current direction of the coil set 211 of the stator 21, such that the stator 21 can change the polarity of the silicon steel plates 212 and 213 in response to the rotor 22.
The Hall sensor 12 outputs a high level signal when detecting the N pole of the rotor 22, and the polarity of the silicon steel plate 212, where the Hall sensor 12 is located, is changed to N pole, such that the rotor 22 is continuously operating by a repulsive force from the N pole to the silicon steel plate 212. On the other hand, the Hall sensor 12 outputs a low level signal when detecting the S pole of the rotor 22, and the polarity of the silicon steel plate 212 is changed to S pole, wherein the operating principle is the same as previously described. However, if a boundary between the N and S poles of the rotor 22 is within a sensing range of the Hall sensor 12, the motor 2 falls into a dead angle. The boundary between the N and S poles of the rotor 22 is determined by a magnetic polarity of the rotor 22.
Therefore, in order to avoid an operational dead angle of the motor 2, one of the typical methods is disposing the Hall sensor 12 on a circuit board 10 and making the Hall sensor 12 to be located in an intermediate zone of the two pole silicon steel plates 212 and 213 of the stator 21, as shown in FIG. 2A. Although this method can provide a switching phase signal without the operational dead angle to the motor driving circuit 11, the method males the maximum efficiency of the motor 2 difficult to control.
Further, referring to FIG. 2B, in order to solve such low efficiency problem, another method is used wherein a location is found with the best efficiency through testing the circuit board 10 between two pole silicon steel plates 212 and 213 of the stator 21, and the Hall sensor 12 is disposed in the location. Although this method can enhance operational efficiency, the operational dead angle still exists.